Preparação e caracterização de argilas organofílicas e sua aplicação na adsorção de atrazina em água
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Data
2017-08-29
Autores
Vazzoler, Fabrícia dos Santos D’Agostini
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Universidade Federal do Espírito Santo
Resumo
Organophilic clays prepared from quaternary ammonium salts stand out as adsorbents for the separation of organic compoundsfrom water. Thus, the purpose of this work was to prepare and characterize three different types of organophilic clays and then to verify the ability of one of these clays to adsorb atrazine in aqueous medium. From the cation exchange process, the naturalclay was modified in organophilic clays, using cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride and dodecyl trimethyl ammonium chloride surfactants. For the clay in natura, the results of the chemical analysis by X-ray fluorescence werecoherent with those of a smectite clay, as well as the result obtained by the cation exchange capacity, which presented a value of 80meq / 100g of clay. The X -ray diffraction data indicate different lamellar expansions for the three organophilic clays obtained when compared to the in naturaclay, proving the presence of quaternary ammonium salts in the interlamellar space. Scanning electron microscopy showed the formation of agglomerations. It was also verified a decrease of the specific surface area demonstrating less accessibility to the lamellar spaces due to the presence of surfactants. The thermogravimetric analyzes were carried out at a constant heating rate up at1000ºC, obtaining a negative variation profile in all the clays, being possible to verify the loss of water and surfactants gradually. The Foster swelling showed strong favoring of adsorption of solvents of nonpolar characteristics, confirming the organophilic character. In addition, the adsorption of atrazine in the chosen organophilic clay was much higher when compared to the in naturaclay, evidencing the potential of using these materials as an alternative to the existing treatments for the removal of organic compounds from water.
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Argilas , Surfactantes , Sais Quaternários de Amônio , Argilas
Citação
VAZZOLER, Fabrícia dos Santos D’Agostini. Preparação e caracterização de argilas organofílicas e sua aplicação na adsorção de atrazina em água. 2017. Dissertação (Mestrado em Química) – Universidade Federal do Espírito Santo, Vitória, 2017.